This invention relates to a method for applying a "nerve block" anesthetic to the eye organ prior to or during ophthalmological surgery, and more particularly, to a method and device that is suitable for deep topical fornix "nerve block" anesthesia.
In 1884, Viennese ophthalmogists developed a technique for cataract eye surgery that used a topical cocaine anesthetic. The technique comprised the application of cocaine eye drops onto the ocular surface. The method was advantageous since it avoided the use of a general anesthetic, which carried greater risks to the patient.
During the first World War, Van Lint and O'Brien produced motor akinesia of the facial nerve. Shortly thereafter, in 1928, Professor Elshnig proposed the technique of retrobulbar injection, which comprises injection of anesthetic into the retrobulbar space of the eye organ using a hypodermic needle.
Since that time, there has been continuing debate about what type of anesthetic technique is appropriate in ocular anterior segment surgery. The retrobulbar injection anesthesia technique produces profound anesthesia (loss of sensation) as well as akinesia (loss of motion) and increased stability of the eye organ globe during surgery. It also facilitates free manipulation of the external as well as internal anterior eye segment structures. However, retrobulbar injection does not anesthetize much of the conjunctival surface.
Traditional topical anesthesia, on the other hand, allows for more rapid onset of the anesthesia to take effect and has less risk of damage to the eye organ. However, in the ophthalmological art, it is generally known that a topical anesthetic produces some degree of patient pain or sensation when making incisions in the sclera and when manipulating the iris and ciliary body.
Recently, Dr. Spencer Thornton developed a technique of "deep topical anesthesia" for radial keratotomy surgery. This technique comprised carefully instilling proparacaine (ophthaine) in the superior and inferior conjunctival fornices of the eye organ. The technique provides primarily for patient comfort; no anesthetic is placed directly on the cornea of the eye, which is more sensitive than the conjunctiva. Instead, the anesthetic is washed onto the cornea as the patient blinks.
While the technique of deep topical anesthesia of Dr. Thornton was advantageous in some respects to conventional topical application, or the technique of retrobulbar injection, it is less than satisfactory since it does not provide profound anesthesia. Specifically, deep topical anesthesia does not promote access of the anesthetic to posterior and deep orbital compartments.
Accordingly, it would be desirable to develop a method or technique for applying an anesthetic to the eye organ prior to or during anterior eye segment surgery, such as cataract surgery or radial keratotomy, which overcomes the disadvantages that are found in prior art techniques.